Editing Gregorian chant (section)

===Rhythm===
Given the oral teaching tradition of Gregorian chant, modern reconstruction of intended rhythm from the written notation of Gregorian chant has always been a source of debate among modern scholars. To complicate matters further, many ornamental neumes used in the earliest manuscripts pose difficulties on the interpretation of rhythm. Certain neumes such as the ''pressus'', pes quassus, strophic neumes may indicate repeated notes, lengthening by repercussion, in some cases with added ornaments. By the 13th century, with the widespread use of square notation, most chant was sung with an approximately equal duration allotted to each note, although [[Jerome of Moravia]] cites exceptions in which certain notes, such as the final notes of a chant, are lengthened.{{sfn|Hiley|1990|p=44}}

While the standard repertory of Gregorian Chant was partly being supplanted by new forms of polyphony, the earlier melo-rhythmic refinements of monophonic chant seem to have fallen into disuse. Later redactions such as the ''Editio medicaea'' of 1614 rewrote chant so that melismata, with their melodic accent, fell on accented syllables.{{sfn|Apel|1990|p=289}} This aesthetic held sway until the re-examination of chant in the late 19th century by such scholars as {{ill|Peter Wagner (musicologist)|de|Peter Wagner (Musikwissenschaftler)|lt=Peter Wagner}}, [[Joseph Pothier|Pothier]], and [[André Mocquereau|Mocquereau]], who fell into two camps.

One school of thought, including Wagner, Jammers, and Lipphardt, advocated imposing rhythmic meters on chants, although they disagreed on how that should be done. An opposing interpretation, represented by Pothier and Mocquereau, supported a free rhythm of equal note values, although some notes are lengthened for textual emphasis or musical effect. The modern Solesmes editions of Gregorian chant follow this interpretation. Mocquereau divided melodies into two- and three-note phrases, each beginning with an ''ictus'', akin to a beat, notated in chantbooks as a small vertical mark. These basic melodic units combined into larger phrases through a complex system expressed by [[cheironomy|cheironomic]] hand-gestures.{{sfn|Apel|1990|p=127}} This approach prevailed during the twentieth century, propagated by [[Justine Ward]]'s program of music education for children, until the liturgical role of chant was diminished after the liturgical reforms of [[Pope Paul VI]], and new scholarship "essentially discredited" Mocquereau's rhythmic theories.{{sfn|Dyer|2001|loc=§VI.1}}

Common modern practice favors performing Gregorian chant with no beat or regular metric accent, largely for aesthetic reasons.{{sfn|Mahrt|2000|p=18}} The text determines the accent while the melodic contour determines the [[Musical phrasing|phrasing]]. The note lengthenings recommended by the Solesmes school remain influential, though not prescriptive.

Dom {{ill|Eugène Cardine|fr}} (1905–1988), a monk from Solesmes, published his 'Semiologie Gregorienne' in 1970 in which he clearly explains the musical significance of the neumes of the early chant manuscripts. Cardine shows the great diversity of neumes and graphic variations of the basic shape of a particular neume, which can not be expressed in the square notation. This variety in notation must have served a practical purpose and therefore a musical significance. Nine years later, the ''Graduale Triplex'' was published, in which the Roman Gradual, containing all the chants for Mass in a Year's cycle, appeared with the neumes of the two most important manuscripts copied under and over the 4-line staff of the square notation. The ''Graduale Triplex'' made widely accessible the original notation of Sankt Gallen and Laon (compiled after 930 AD) in a single chantbook and was a huge step forward. Dom Cardine had many students who have each in their own way continued their semiological studies, some of whom also started experimenting in applying the newly understood principles in performance practice.

The studies of Cardine and his students (Godehard Joppich, Luigi Augustoni, Johannes B. Göschl, Marie-Noël Colette, Rupert Fischer, Marie-Claire Billecocq, [[Alexander M. Schweitzer]] to name a few) have clearly demonstrated that rhythm in Gregorian chant as notated in the 10th century rhythmic manuscripts (notably Sankt Gallen and Laon) manifest such rhythmic diversity and melodic – rhythmic ornamentations for which there is hardly a living performance tradition in the Western world. Contemporary groups that endeavour to sing according to the manuscript traditions have evolved after 1975. Some practising researchers favour a closer look at non-Western (liturgical) traditions, in such cultures where the tradition of modal monophony was never abandoned.

Another group with different views are the mensuralists or the proportionalists, who maintain that rhythm has to be interpreted proportionately, where shorts are exactly half the longs. This school of interpretation claims the support of historical authorities such as St Augustine, Remigius, Guido and Aribo.<ref>{{cite web|url=http://www.calumcille.com/griogair/9A14.html |title=The symbolism of chant rhythm |publisher=Calumcille.com |access-date=2012-06-06 |url-status=dead|archive-url=https://web.archive.org/web/20120315074741/http://www.calumcille.com/griogair/9A14.html |archive-date=15 March 2012 }}</ref> This view is advocated by John Blackley and his 'Schola Antiqua New York'.

Recent research in the Netherlands by Dr. Dirk van Kampen has indicated that the authentic rhythm of Gregorian chant in the 10th century includes both proportional elements and elements that are in agreement with semiology.<ref>van Kampen, Dirk (1994). ''Het oorspronkelijke ritme van het Gregoriaans: Een 'semiologisch-mensuralistische' studie''. Landsmeer, {{ISBN|90-900742-8-7}}. (in Dutch)</ref><ref>{{cite journal | last1 = van Kampen | first1 = Dirk | year = 2005 | title = Uitgangspunten voor de ritmiek van Gregoriaans | journal = Tijdschrift voor Gregoriaans|language=nl| volume = 30 | pages = 89–94 }}</ref> Starting with the expectation that the rhythm of Gregorian chant (and thus the duration of the individual notes) anyway adds to the expressivity of the sacred Latin texts, several word-related variables were studied for their relationship with several neume-related variables, exploring these relationships in a sample of introit chants using such statistical methods as correlational analysis and multiple regression analysis.

Beside the length of the syllables (measured in tenths of seconds), each text syllable was evaluated in terms of its position within the word to which it belongs, defining such variables as "the syllable has or has not the main accent", "the syllable is or is not at the end of a word", etc., and in terms of the particular sounds produced (for instance, the syllable contains the vowel "i"). The various neume elements were evaluated by attaching different duration values to them, both in terms of semiological propositions (nuanced durations according to the manner of neume writing in Chris Hakkennes' ''Graduale Lagal''<ref>Chris Hakkennes (1984). ''Graduale Lagal''. Den Haag: Stichting Centrum voor de Kerkzang.</ref>), and in terms of fixed duration values that were based on mensuralistic notions, however with ratios between short and long notes ranging from 1 : 1, via 1 : 1.2, 1 : 1.4, etc. to 1 : 3. To distinguish short and long notes, tables were consulted that were established by Van Kampen in an unpublished comparative study regarding the neume notations according to Sankt Gallen and Laon codices. With some exceptions, these tables confirm the short vs. long distinctions in Cardine's 'Semiologie Gregorienne'.

The lengths of the neumes were given values by adding up the duration values for the separate neume elements, each time following a particular hypothesis concerning the rhythm of Gregoriant chant. Both the syllable lengths and the neume lengths were also expressed in relation to the total duration of the syllables, resp. neumes for a word (contextual variables). Correlating the various word and neume variables, substantial correlations were found for the word variables 'accented syllable' and 'contextual syllable duration'. Moreover, it could be established that the multiple correlation (''R'') between the two types of variables reaches its maximum (''R'' is about 0.80) if the neumatic elements are evaluated according to the following rules of duration: (a) neume elements that represent short notes in neumes consisting of at least two notes have duration values of 1 time; (b) neume elements that represent long notes in neumes consisting of at least two notes have duration values of 2 times; (c) neumes consisting of only one note are characterized by flexible duration values (with an average value of 2 times), which take over the duration values of the syllables to match.

The distinction between the first two rules and the latter rule can also be found in early treatises on music, introducing the terms ''metrum'' and ''rhythmus''.<ref>{{ill|Peter Wagner (musicologist)|de|Peter Wagner (Musikwissenschaftler)|lt=Peter Wagner}} (1916). "Zur ursprünglichen Ausführung des Gregorianischen Gesanges". ''Gregoriusblatt'', 81–82. (in German)</ref><ref>{{cite journal | last1 = Jeannin | first1 = J. | year = 1930 | title = Proportionale Dauerwerte oder einfache Schattierungen im Gregorianischen Choral? | journal = Gregoriusblatt|language=de| volume = 54 | pages = 129–135 }}</ref> As it could also be demonstrated by Van Kampen that melodic peaks often coincide with the word accent (see also),<ref>G. Reese (1940). ''Music in the Middle Ages''. New York: Norton & Comp., p. 166.</ref> the conclusion seems warranted that the Gregorian melodies enhance the expressiveness of the Latin words by mimicking to some extent both the accentuation of the sacred words (pitch differences between neumes) and the relative duration of the word syllables (by paying attention to well-defined length differences between the individual notes of a neume).

During the seventeenth through nineteenth centuries in France, the system of rhythmic notation became standardized, with printers and editors of chant books employing only four rhythmic values. Recent research by Christopher Holman indicates that chants whose texts are in a regular meter could even be altered to be performed in [[time signature]]s.<ref>{{Cite journal|last=Holman|first=Christopher|date=November 2017|title=Rhythm and metre in French Classical plainchant|url=https://academic.oup.com/em/article-abstract/45/4/657/4781684|journal=Early Music|volume=45, vol. 4|issue=4|pages=657–664|doi=10.1093/em/cax087}}</ref>